Abstract/Summary

Outstanding flood events are particularly influential in
relation to the development of engineering design
procedures and flood mitigation strategies. However,
uncertainties concerning the credibility of peak flow
assessments associated with many exceptional historical
flood events can limit their utility. This paper uses a
combination of historical and hydrometric evidence,
together with contemporary rainfall–runoff modelling
procedures, to examine the highest recorded flow on
the River Thames. The evidence strongly suggests that
the generally accepted maximum flow for the
November 1894 flood is substantially overestimated.
A synthesis of the historical evidence, and estimates
from two rainfall–runoff models, allows a more
realistic estimate of the peak flow to be derived.
Its impact on return period assessments is
considered within the wider context of the limited
precision and availability of extreme flood flow
estimates in the UK.